Abstract: Objective　To analyze the epidemiological and clinical characteristics of the Japanese encephalitis outbreak cases in Shijiazhuang city in 2013,so as to provide a basis for early warning of Japanese encephalitis outbreak.Methods　The clinical data and follow-up data of Japanese encephalitis patients were collected，and healthy residents in the villages of Gaocheng,Wuji,Pingshan and Jingxing County were selected as study subjects,Japanese encephalitis cases were found in these villages,serum Japanese encephalitis antibody level of subjects was detected during Japanese encephalitis.The Japanese encephalitis antibody data in Shijiazhuang in 2003 were collected as historical control.Mosquito monitoring was conducted by the mosquito lure lamp in the county which had outbreak of an epidemic,and adult mosquitoes were collected for counting and classification identification.Results　From 26 August to 5 November in 2013,a total of 121 Japanese encephalitis cases were reported by medical institutions in Shijiazhuang city,there were 101 cases（83.5%） and 20 cases（16.5%） from rural area and urban area respectively,male-to-female sex ratio was 0.92∶1.96 cases（79.3%） were 20 years of age or older,73 cases（60.3%） were farmers.Median time from disease onset to hospital admission was 2 days,and median time from disease onset to diagnosis was 17 days.Serum of 94 cases were collected to detect Japanese encephalitis IgM antibody,among which 79 were positive,the positive rate was 84.0%.50.0% of cases or more presented with acute onset,fever,depression,disturbance of consciousness.105 cases were followed up,among whom 35 cases（33.3%） had sequelae,11 cases（10.5%） died.Only 6 cases（5.0%） had a history of Japanese encephalitis vaccination.The positive rate of Japanese encephalitis antibody among healthy people in Shijiazhuang in 2013〔13.4%（114/850）〕 was significantly lower than that in 2003〔30.9%（122/395）〕（P<0.05）.The positive rate of Japanese encephalitis antibody among healthy people of 10-19 years old and 20-29 years old in 2013 was significantly lower than that in 2003 respectively（P<0.05）.641 mosquitos,we collected,included 600（93.6%） culex pipiens pallens,25（3.9%） armigeres subalbatus,and 16（2.5%）patton malaria mosquitos.Conclusion　The characteristics of Japanese encephalitis outbreak in Shijiazhuang in 2013 includ more adult cases,high risks of sequela and death,and low Japanese encephalitis antibody positive rate among healthy people.Close attention should be paid to population’s antibody levels and mosquito density variations,epidemic surveillance of Japanese encephalitis should be strengthened for early detection and effective control.

Key words: Encephalitis,Japanese, Disease outbreaks, Adult, Culex

摘要： 目的　分析2013年石家庄市流行性乙型脑炎（简称乙脑）暴发疫情患者的流行病学和临床特征，为乙脑疫情的早期预警提供依据。方法　收集本次乙脑暴发疫情患者临床资料和随访资料。于本次疫情暴发期间（2013年10月中旬）选择藁城市、无极县、平山县和井陉县有乙脑病例发生的村进行健康人群血清乙脑抗体检测。收集2003年石家庄市乙脑抗体检测资料作为历史对照。在疫情发生县采用诱蚊灯法进行蚊种监测，收集成蚊进行计数和分类鉴定。结果　2013-08-26至11-05，石家庄市医疗机构共报告乙脑患者121例，其中农村101例（83.5%），市区20例（16.5%）；男女性别比为0.92∶1；20岁及以上患者占全部患者的79.3%（96/121）；职业以农民为主,共73例（60.3%）。患者发病后中位就诊时间为2 d,发病后中位诊断时间为17 d。94例采集血清进行乙脑病毒IgM抗体检测，其中阳性79例，阳性率为84.0%。50.0%及以上的患者表现有急性起病、发热、精神萎靡、意识障碍。随访到的105例患者有后遗症35例（33.3%）,死亡11例，病死率为10.5%。6例（5.0%）有乙脑疫苗接种史。2013年石家庄市健康人群乙脑抗体阳性率为13.4%（114/850），低于2003年的30.9%（122/395）（P<0.05）；其中2013年10岁～及20岁～健康人群乙脑抗体阳性率低于2003年（P<0.05）。2013年监测到的641只蚊中，淡色库蚊600只（93.6%），骚扰阿蚊25只（3.9%），帕氏按蚊16只（2.5%）。结论　2013年石家庄市乙脑暴发疫情呈现成年人患者增多的特点，后遗症和死亡风险较高，健康人群乙脑抗体阳性率较低。需密切关注人群抗体水平、蚊媒密度变化，加强乙脑疫情监测，及早发现流行态势以有效控制疫情。

关键词: 脑炎, 日本, 疾病暴发流行, 成年人, 库蚊属